This is part of the weekly Blogging Challenge over at Long and Short Reviews. If you'd like to participate, you can find the prompts here. They also put up a post every Wednesday where you go and link your response -- and see everyone else's. Check out their homepage to find it.
The challenge for this week is "favorite tropes of X genre".
So, for genre I'm going with horror, and for my favorite trope I'm going with The Character Who Can Fight The Monsters Because They're Somehow Related To Them.
Think about Ellen Ripley in Alien: Resurrection: having been cloned back to life with a bit of xenomorph DNA, she has a sense of where the aliens (and especially the queen) are located, and enhanced physical abilities. It's not enough to let her take on even a single xenomorph directly, but it gives her a distinct advantage in trying to get the survivors off the ship when they get loose.
Or think about Blade (probably best known from the movies, but originally a Marvel Comic): his mother was attacked by a vampire while pregnant, and he was born as a sort of halfbreed, able to match their physical abilities but without many of their weaknesses.
But even more dear to me is a sort of sub-set of this trope: characters who fight monsters by becoming monsters themselves. Probably the most obvious example, the one people might recognize, is Ben Tennyson of the Ben 10 series, who uses a mysterious alien device called the Omnitrix to turn into any of a selection of different alien monsters, and then uses their powers to fight various sorts of alien and mad-science threats.
But my personal favorite is a bit darker: Yuri Hyuga from the video game Shadow Hearts. Yuri is a Harmonixer, possessing the magical ability to transform into supernatural monsters, and to absorb the souls of the monsters he defeats. The ability has a price, however; as those souls add up, they start to drag him down, and eventually a mysterious fox-mask character shows up in a sort of dream graveyard to try to defeat him and take him over.
So there you go: one of my favorite tropes. What are yours?